1. Field of the Invention
This invention relates generally to current amplification means and methods, and more particularly relates to systems, apparatus, and methods for current amplification by impact ionization.
2. Description of the Related Art
The invention presented herein was developed in an effort to create an electronic device capable of producing impact ionization based current gain for a signal from an arbitrary current source. Other devices such as avalanche photodiodes and IMPATT diodes utilize impact ionization gain, but the current sources for these structures reside within the depletion regions of the devices themselves. Consequently, an attempt to “wire up” a current source to one of these devices would result in no current gain.
Impact ionization based gain is attractive because it can provide very low noise amplification for small current signals. The value of impact ionization based gain is easily illustrated by the continued use and development of avalanche photodiodes for the detection of low light signals. Avalanche photodiodes provide an additional gain to a photocurrent generated within their depletion regions while operating below the noise floor of transistor based amplifiers (transimpedance amplifiers) used to convert current into readable voltage levels. Levels of light can thus be detected that would be indistinguishable without the additional gain provided by the avalanche photodiodes.
From the foregoing discussion, it should be apparent that a need exists for a system, apparatus, and method that leverage the current gain characteristics of impact ionization to enable amplification of a signal provided by an arbitrary current source.